Digital display indicator

ABSTRACT

A digital display indicator wherein a plurality of numerals are carried on a rotatable drum 38 so that the numerals may be successively brought into position behind a viewing window 52. An eccentrically mounted drive finger 74 accurately indexes a ratchet wheel of the rotatable drum from one position to a next succeeding position while the finger holds a spring loaded detent lever away from the ratchet wheel.

I PATENTEDUECZS I975 3.780.524

sum u [If 4 BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to a digital display indicator, and more particularlyto a display indicator wherein a plurality of numerals are carried on arotatable member so that the numerals may be successively brought intoposition behind a viewing window.

With such a digital indicator it is especially desirable that theindexing of the rotatable member from one numeral to a next succeedingnumeral occur relatively rapidly in about five seconds of time. Thus,the numerals are indexed in an intermittent fashion rather than beinggradually and continuously moved into position behind a viewing window.

2. Description of the Prior Art The prior art includes many differentconstructions and arrangements for quickly moving clock numerals andother numerals from one position to a next succeeding position. Genevagears are frequently employed, and for example, in one prior artconstruction as shown in U.S. Pat. No. 2,040,421 to Almquist dated May12, 1936, a Geneva wheel 67 is utilized for rapidly indexing a numeraldisc 69.

In another prior art construction as shown in a patent to Clark, U.S.Pat. No. 2,748,560 dated June 5, 1956, there is shown a rotatableactuating finger mechanism 6l which is positioned within a numeral drumfor rapidly indexing the drum from one numeral to the next succeedingnumeral.

With such digital display indicators it is also desirable that thenumerals be held in a particular viewing position after they have beenindexed, and for example, it is especially desirable in a clock that thenumerals for indicating hours, tens of hours and minutes be displayedand held in line behind a viewing aperture or lens. In a prior patent toMeyer, U.S. Pat. No. 2,968,143 dated Jan. 17, l96l, a spring member 6 isprovided for holding a star wheel and an hour wheel It is also an objectof my invention to provide an improved digital display indicator whichhas very low torque requirements.

SUMMARY OF THE INVENTION In accordance with one of the aspects of thisinvention, a digital indicator includes a rotatable indicator memberhaving a plurality of numerals arranged thereon in sequential order sothat the numerals may be successively brought into a viewing position. Atoothed wheel is fixed to the rotatable indicator member and is mountedfor rotation with the indicator member. A spring loaded lever is mountedadjacent to the toothed wheel and is spring urged into engagement withthe teeth of the wheel for holding the numerals of the rotatableindicator member in particular viewing positions. A drive member ispositioned adjacent to the wheel for incrementally moving the wheel tobring successive numerals into a viewing position. The drive member hasan axis which is spaced from the axis of the toothed wheel and themember is provided with an eccentric drive finger for contacting one ofthe teeth of the wheel each time the drive member makes a revolution.

With this construction, the drive finger advances the sprocket and therotatable indicator member an angular distance corresponding to thatnecessary to bring the next numeral of the rotatable indicator memberinto a viewing position. The relative locations of the teeth of thewheel and the spring loaded lever with respect to the path of movementof the drive finger are such that upon rotation of the drive finger in awheel advancing direction, the finger first contacts the lever togradually lift the lever out of engagement with the teeth of the wheeland drive finger then holds the de- 7 to which it is attached in anappropriate position behind a viewing window 10. Other spring loadeddetent and ratchet type mechanisms have also been utilized for holdingnumeral drums in their appropriate positions, and one of the problemswith such mechanisms is that they usually emit clicking sounds as thespring loaded members are inserted between the teeth of a gear orratchet. I

This invention is concerned with such digital display indicators, andmore particularly, to a unique construction for holding a rotatablenumeral drum behind a viewing window and for quickly advancing thenumeral drum from one position to a next succeeding position.

Accordingly, it is a primary object of my invention to provide animproved digital display indicator which may be reliably and quicklyindexed from one numeral to a next succeeding numeral, and wherein therotatable indicator member may be held in its appropriate viewingposition without the use of mechanisms that emit clicking noises whichare commonly associated with spring loaded detents.

It is a further object of my invention to provide an improved digitaldisplay indicator having relatively few parts which may be readilymanufactured and assembled to each other.

tent lever away from the sprocket while the finger engages one of theteeth of the wheel to move the wheel and the rotatable indicator memberto the next numeral position. Then, continued rotation of the fingergradually lowers the detent lever into a position on a tooth of thesprocket to permit the detent lever to hold the wheel and the rotatableindicator member in an appropriate numeral viewing position.

By this arrangement, the drive finger reliably and accurately quicklymoves the wheel and the rotatable indicator member from one numeralposition to the next numeral position in a relatively short indexingperiod of time, and moreover, the drive finger cooperates with thedetent lever to gradually raise and lower the detent lever to itsholding position so that the detent lever does not make anyobjectionable clicking noises as it is moved into and out of engagementwith the toothed wheel.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and attendant advantagesof the invention will be apparent from the following description takenin connection with the accompanying drawing in which:

FIG. 1 is a front perspective view of a digital clock constructed inaccordance with my invention;

FIG. 2 is a front perspective view generally similar to FIG. I with theouter casing removed for purposes of illustration;

FIG. 3 is a fragmentary exploded front perspective view of the clockillustrated in FIGS. 1 and 2;

FIG. 4 is a front elevational view of the clock shown in FIG. 2;

FIG. 5 is a cross-sectional view of the clock taken substantially on theplane of 5-5 of FIG. 4;

FIG. 6 is a cross-sectional view of the digital clock takensubstantially on the plane of 6-6 of FIG. 4 showing one of the numeralpages being flipped to display a numeral on the other side of the page;

FIG. 7 is a cross-sectional view of the clock also taken on the plane of6-6 of FIG. 4 showing the numeral pages in a different operatingposition;

FIG. 8 is a cross-sectional view of the clock taken substantially on theplane of 88 of FIG. 4;

FIG. 9 is a cross-sectionalview of the clock taken substantially on theplane 9-9 of FIG. 4 showing the details of construction of my uniquedrive finger and detent lever for advancing a minutes drum from oneposition to a next succeeding position and for holding the minutes drumin an accurate viewing position, the parts being shown with the detentlever holding the ratchet wheel of the minutes indicator member in anaccurate viewing position;

FIG. 10 is a cross-sectional view of the digital clock also takensubstantially on the plane of 9-9 of FIG. 4 showing my improved drivefinger arrangement with the finger holding the detent lever away fromthe ratchet wheel while the finger moves the ratchet wheel from oneposition to a next succeeding position; and

FIG. 11 is a cross-sectional view of the digital clock also takensubstantially on the plane of 9-9 of FIG. 4 showing the finger graduallylowering the detent lever onto one of the teeth of the ratchet wheel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing,and first particularly to FIGS. 1 and 2, there is shown a digital clockwhich includes my unique mechanism for indexing and holding a displayindicator without making undesired noise such as clicking sounds whichsometimes occur in devices of this type. As shown, the digital clocknumerals may conventionally include three sets of pages 2, 4 and 6 forindicating minutes, tens of minutes, and hours, respectively.

The digital clock may be driven by a conventional self-startingsynchronous motor 8 having a magnetic core 10 and energizing coil 12. Asshown in FIG. 2, the motor may be readily attached to an end plate 14 ofthe clock by means of screws 16 and 18 or other suitable securing means.As shown more particularly in FIGS. 2, 3, 6 and 7, the minutes numeralsare printed or otherwise formed on both sides of five pages 24, 26, 28,30 and 32, and the pages are pivotally mounted on flanges 34 and 36 ofthe rotatable minutes drum 38.

As shown more particularly in FIG. 5, the minutes spool drum 38 is fixedto a centrally positioned shaft 40 by means of knurling 43 or othersuitable connecting means. As shown, the shaft 40 extends a considerabledistance to the left of the spool and is supported for rotation within aconcentric hollow shaft 42 of a tens of minutes display indicator drum44. The right end portion 72 of the shaft 40 is rotatably supportedwithin a hearing 48 which is integrally formed with a supporting Thedetails of the tens of minutes, and hours display indicators 4 and 6,and the Geneva drive mechanisms for actuating these display indicatorsdo not form a part of this invention and are described and illustratedin greater detail in my copending application (6D-4474), Ser. No.339,213, filed Mar. 8, I973, assigned to the same assignee as thepresent invention.

MINUTES INDEXING AND HOLDING CONSTRUCTION In accordance with myinvention the minutes drum 38 is quickly indexed from one numeralposition to a next succeeding numeral position in about five seconds oftime, and it is uniquely held in appropriate positions to displaynumerals midway between the upper and lower edges of a viewing window 52illustrated in FIG. 1. As shown more particularly in FIGS. 3 and 5, aratchet wheel 56 having five teeth 58, 60, 62, 64 and 66, may beintegrally formed with the drum 38 for incrementally driving the drum.

A drive finger 74 is eccentrically mounted for rotation with respect tothe ratchet wheel to engage and move one tooth of the ratchet wheel foreach revolution of the drive finger 74. -As shown more particularly inFIGS. 3 and 5, the drive finger 74 may be integrally formed on areduction gear unit 76 which is positioned between the output shaft 20of the electric motor 8 and the ratchet wheel 56. A shaft 78 isintegrally formed with the reduction gear unit 76 and is mounted forrotation within apertures 80 which are provided in mounting plates 14and 50. The apertures 80 are located somewhat rearwardly of the axis ofthe ratchet wheel 56 in order to provide the desired eccentricitybetween the ratchet teeth and the drive finger 74. With thisconstruction, the output pinion 20 of the motor drives a gear 84 of theintegrally formed reduction gear unit 76 to move the drive finger 74atone revolution per minute. With reference to FIG. 3, it can beappreciated that the drive finger 74 will remain in engagement with atooth of the ratchet wheel 56 for about 30 degrees of travel of thereduction gear unit 76, and accordingly, movement of the minutes numeraldrum 38 from one position to a next succeeding position will occur inthe relatively short span of about five seconds.

A uniquely shaped and positioned detent lever is provided for holdingthe sprocket 56 in any one of a plurality of numeral positions. As shownmore particularly in FIGS. 3 and 9, the detent lever is elongated andcurved to partially surround the sprocket. It may be formed of a singlepiece of plastic and includes a detent notch 92 for receiving one of theteeth of the sprocket wheel, and an integrally formed pivot pin 98 whichis mounted in apertures 94 and 96 which may be conveniently formed inplates 50 and 14 respectively. The central portion of the lever includesan enlarged lug portion 100 for receiving spring 102 to urge the leverin a counterclockwise direction as shown in FIG. 3 or a clockwisedirection as viewed in FIG. 9. As shown, the spring is coiled around thelug 100 and one end of the spring 102 is held by an outwardly extendingfinger 104 which may be integrally formed with the detent lever 74 whilethe other end of the spring 102 may be positioned under a lug 106 whichextends between plates 14 and 50.

As shown more particularly in FIGS. 9 and 10, a cam surface 108 isformed on one side of the detent notch 92 for cooperating with the drivefinger 74 to permit the drive finger to gradually move into engagementwith the detent lever, 90 to lift the detent notch 92 above the ratchetwheel so that the drive finger 74 may then engage and move one of theratchet teeth 60 from one incremental position to the next succeedingincremented position. A cam surface 110 is formed on the other side ofthe detent lever notch 92 for gradually lowering the detent notch 92over the next succeeding ratchet tooth to be indexed in order to holdthe minutes drive wheel so that one of the numerals is accuratelydisplayed midway between the upper and lower edges of the viewing window52. Thus, the cam surfaces 108 and 110 of the detent lever are uniquelyrelated to the drive finger 74 so that the drive finger gradually raisesand lowers the detent lever without causing an objectionable clickingnoise.

With particular reference to FIGS. 9, l and 11, it can be appreciatedthat the camsurface 108 for gradually lifting the detent lever 90against the force of spring 102 is relatively long and is positionedwith respect to the drive finger 74 so that the finger is placed incontact with it for about of the rotation of the drive finger 74 priorto the point where the drive finger engages a tooth of the ratchetwheel. Thus, the torque required for lifting the detent lever 90 at agiven instant is relatively low since the force is applied over arelatively long period of time.

It can also be appreciated from FIGS. 9, l0 and 11 that the principalportion of ratchet wheel 56 is located within the path of movement ofthe drive finger 74. Such a construction has lower torque requirementsthan a conventional interengaging gear wheel construction whereinsubstantial portions of the paths of movements of the gears are spacedfrom each other and do not envelop each other. As shown moreparticularly in FIG. 10 of applicant, it can be appreciated that withthis construction there is less sliding friction between the drivefinger and the ratchet wheel and accordingly, the torque required forlifting the detent lever and indexing the ratchet wheel is relativelylow.

, In accordance with my invention, the mechanism for flipping pages todisplay numerals which are formed on both sides of the pages is uniquelyincorporated with supporting plate 50 in order to achieve an inexpensivedisplay indicator having relatively few parts. As shown moreparticularly in FIGS. 3, 5 6 and 7, a generally circular skirt member114 is integrally formed with the plate 50 and extends outwardly to theleft in order to the left in order to flip the pages. As shown in FIGS.6 and 7 the generally circular skirt 114 does not extend 360 degrees butis formed with a gap or cutout portion 116 of approximately 30 degreesfor tipping and flipping the display pages 24, 26, 28, 30 and 32. Withthis construction, as the drum 38 is rotated in the direction of thearrow shown in FIG. 6, when one of the pages reaches the cutout portion1 16 of the skirt it is not confined by the skirt and the leadingportion of the page moves outwardly beyond the skirt. Thus, as the pagesmoves through the gap or cutout portion of the skirt, it abuts a loweredge cam portion 118 of the skirt which flips the page to display a newnumeral. It can be appreciated that after the page has been flipped todisplay a numeral which had been positioned on the back side of thepage, the skirt 114 will hold the page in its desired position until itagain reaches the gap 116 in the skirt.

OPERATION In operation, the output pinion 20 of the synchronous motor 8rotates gear 84 of the reduction gear unit 76 to move the drive finger74 at one revolution per minute. The drive finger engages cam surface108 of the detent lever to gradually lift the detent notch 92 againstthe force of spring 102. The drive finger 74 then contacts and moves oneof the teeth of the ratchet wheel 56 from one numeral position to thenext succeeding numeral position, and the drive finger 74 then graduallylowers the detent lever to position the detent notch 92 on top of thenext succeeding tooth to be indexed in order to accurately hold one ofthe minutes numerals in an appropriate viewing position.

With particular reference to FIGS. 6 and 7, it can be seen that whilethe pages which are located at the front of the display indicator arebeing moved from one display position to the next succeeding numeralposition, the pages at the rear of the display indicator are beingflipped so that the numeral which had been facing inwardly is flipped toface outwardly. As the drum 38 is rotated the pages at the rear of thedisplay indicator are flipped by the cam portion 118 of the skirt.

From the foregoing discussion, it will be appreciated that my improvedconstruction for indexing and holding a display indicator in appropriateviewing positions may be readily with relatively few parts. The ratchetwheel 56 may be integrally formed with the minutes drum 38 at the timethat the entire minutes drum or spool is being molded from suitableplastic. In like manner, the drive finger 74 and the reduction gear unit76 including its integrally formed shaft 78 may be formed in a singlemolding operation. These parts are uniquely and inexpensively held onthe digital clock by simply forming apertures in the mounting plates 14and 50.

With my improved indexing mechanism it can also be appreciated that thedigital display indicator is quickly moved from one number to the nextsucceeding number in a relatively short period of time, and the numeralsare held in their appropriate viewing positions by a spring loadeddetent lever which is relatively quietly operated by the drive finger74.

What I claim is:

1. A digital indicator for visually displaying numerals comprising:

a. a rotatable indicator member having a plurality of numerals arrangedthereon in sequential order so that they may be successively broughtinto a viewing position;

b. a toothed wheel fixed to said indicator member for rotationtherewith;

c. a lever having a surface for engaging successive teeth of saidtoothed wheel for holding the numerals of said rotatable indicatormember in particular viewing positions;

d. spring means for urging the surface of said lever toward the teeth ofsaid toothed wheel;

e. a drive member for incrementally moving said toothed wheel to bringsuccessive numerals into a viewing position, said drive member beingfixed to a shaft spaced from said toothed wheel and said drive memberhaving a drive finger for contacting one of the teeth of said toothedwheel each time the drive member makes a revolution, the drive fingeradvancing the toothed wheel and said rotatable indicator member anangular distance corresponding to that necessary to bring the nextnumeral of the rotatable indicator into a viewing position; and

f. said lever being positioned in the path of said drive finger suchthat upon rotation of the drive finger the lever is moved away from theteeth of the toothed wheel by the drive finger thereby enabling thedrive finger to contact one of the teeth of the toothed wheel to advancethe toothed wheel and the indicator member to a succeeding numeralposition.

2. A digital indicator as defined in claim 1 wherein said lever includesa notch for engaging one of the teeth of said ratchet for holding thetoothed wheel and the rotatable indicator member in an appropriatenumeral viewing position.

3. A digital indicator as defined in claim 2 wherein said lever includescam surfaces on opposite sides of said notch for cooperation with saiddrive finger, said drive finger contacting one of said cam surfaces tolift the lever above the teeth of the toothed wheel and said fingercontacting and sliding on the other can surface for gradually loweringthe lever to position the notch of the lever on one of the teeth of thetoothed wheel so that the lever does not make any objectionable clickingnoises as it is moved into and out of engagement with the toothed wheel.

4. A digital indicator as defined in claim 1 wherein the digitalindicator also includes:

a. a pair of mounting plates arranged generally parallel to each otherfor supporting said lever and other components of said digitalindicator, said lever being formed from a single piece of plastic andfurther including an integrally formed pivot pattern extending generallyperpendicular to the main body portion of the lever; and

b. an aperture formed in each of said mounting plates for pivotallysupporting said lever between the plates.

5. A digital indicator as defined in claim 4 wherein said lever furtherincludes an outwardly extending tab integrally formed at one end of thelever, and said digital indicator also includes:

a. a spacer post arranged generally perpendicular to said mountingplates and positioned therebetween for supporting said mounting plateswith respect to each other; and

b. a spring having two end portions and a coiled central portion, thecoiled central portion being positioned around the pivot portion of thedetent lever, one of the end portions of said spring being in contactwith the tab on the detent lever and the other end portion of the springbeing in contact with the spacer post for resiliently urging the detentlever into contact with the teeth of said toothed wheel.

6. A digital indicator as defined in claim 4 wherein one of saidmounting plates includes a skirt having a gap integrally formedtherewith, said skirt extending outwardly form the mounting plate towardsaid rotatable indicator member for holding the pages in appropriatedisplay positions and for flipping the pages from one numeral to anothernumeral.

7. A digital indicator as defined in claim 1 wherein said drive memberfor incrementally moving said toothed wheel includes an integrallyformed gear, an axial pivot fixed to said gear, an enlarged wheel fixedto said gear, and a drive finger fixed to an outer surface of saidenlarged wheel.

8. A digital indicator as defined in claim 1 wherein said digitalindicator also includes:

a. an integrally formed gear, an axial pivot fixed to said gear, anenlarged wheel fixed to said gear, and a drive finger fixed to an outersurface of said enlarged wheel;

b. a pair of mounting plates arranged generally parallel to each otherfor supporting said lever and other components of said digitalindicator, said lever being formed from a single piece of plastic andfurther including an integrally formed pivot portion extending generallyperpendicular to the main body portion of the lever; and

c. an aperture formed in each of said plates for rotatably supportingsaid lever.

9. A digital indicator as defined in claim 1 wherein the drive memberhas a path of movement which is greater than the diameter of saidtoothed wheel and the major portion of said toothed wheel is positionedwithin the path of movement of said drive member.

1. A digital indicator for visually displaying numerals comprising: a. arotatable indicator member having a plurality of numerals arrangedthereon in sequential order so that they may be successively broughtinto a viewing position; b. a toothed wheel fixed to said indicatormember for rotation therewith; c. a lever having a surface for engagingsuccessive teeth of said toothed wheel for holding the numerals of saidrotatable indicator member in particular viewing positions; d. springmeans for urging the surface of said lever toward the teeth of saidtoothed wheel; e. a drive member for incrementally moving said toothedwheel to bring successive numerals into a viewing position, said drivemember being fixed to a shaft spaced from said toothed wheel and saiddrive member having a drive finger for contacting one of the teeth ofsaid toothed wheel each time the drive member makes a revolution, thedrive finger advancing the toothed wheel and said rotatable indicatormember an angular distance corresponding to that necessary to bring thenext numeral of the rotatable indicator into a viewing position; and f.said lever being positioned in the path of said drive finger such thatupon rotation of the drive finger the lever is moved away from the teethof the toothed wheel by the drive finger thereby enabling the drivefinger to contact one of the teeth of the toothed wheel to advance thetoothed wheel and the indicator member to a succeeding numeral position.2. A digital indicator as defined in claim 1 wherein said lever includesa notch for engaging one of the teeth of said ratchet for holding thetoothed wheel and the rotatable indicator member in an appropriatenumeral viewing position.
 3. A digital indicator as defined in claim 2wherein said lever includes cam surfaces on opposite sides of said notchfor cooperation with said drive finger, said drive finger contacting oneof said cam surfaces to lift the lever above the teeth of the toothedwheel and said finger contacting and sliding on the other can surfacefor gradually lowering the lever to position the notch of the lever onone of the teeth of the toothed wheel so that the lever does not makeany objectionable clicking noises as it is moved into and out ofengagement with the toothed wheel.
 4. A digital indicator as defined inclaim 1 wherein the digital indicator also includes: a. a pair ofmounting plates arranged generally parallel to each other for supportingsaid lever and other components of said digital indicator, said leverbeing formed from a single piece of plastic and further including anintegrally formed pivot pattern extending generally perpendicular to themain body portion of the lever; and b. an aperture formed in each ofsaid mounting plates for pivotally supporting said lever between theplates.
 5. A digital indicator as defined in claim 4 wherein said leverfurther includes an outwardly extending tab integrally formed at one endof the lever, and said digital indicator also includes: a. a spacer postarranged generally perpendicular to said mounting plates and positionedtherebetween for supporting said mounting plates with respect to eachother; and b. a spring having two end portions and a coiled centralportion, the coiled central portion being positioned around the pivotportion of the detent lever, one of the end portions of said springbeing in contact with the tab on the detent lever and the other endportion of the spring being in contact with the spacer post forresiliently urging the detent lever into contact with the teeth of saidtoothed wheel.
 6. A digital indicator as defined in claim 4 wherein oneof said mounting plates includes a skirt having a gap integrally formedtherewith, said skirt extending outwardly form the mounting plate towardsaid rotatable indicator member for holding the pages in appropriateDisplay positions and for flipping the pages from one numeral to anothernumeral.
 7. A digital indicator as defined in claim 1 wherein said drivemember for incrementally moving said toothed wheel includes anintegrally formed gear, an axial pivot fixed to said gear, an enlargedwheel fixed to said gear, and a drive finger fixed to an outer surfaceof said enlarged wheel.
 8. A digital indicator as defined in claim 1wherein said digital indicator also includes: a. an integrally formedgear, an axial pivot fixed to said gear, an enlarged wheel fixed to saidgear, and a drive finger fixed to an outer surface of said enlargedwheel; b. a pair of mounting plates arranged generally parallel to eachother for supporting said lever and other components of said digitalindicator, said lever being formed from a single piece of plastic andfurther including an integrally formed pivot portion extending generallyperpendicular to the main body portion of the lever; and c. an apertureformed in each of said plates for rotatably supporting said lever.
 9. Adigital indicator as defined in claim 1 wherein the drive member has apath of movement which is greater than the diameter of said toothedwheel and the major portion of said toothed wheel is positioned withinthe path of movement of said drive member.